The highly publicized problem of cardio-vascular diseases, an increased population living excess of 80, and the predominance of the heart disease as a leading cause of death have increased the importance of the clinical practioner's ability to recognize abnormal heart conditions. One of the most powerful instruments for non-invasive heart diagnostics is auscultation. Traditionally, auscultation is based on a physician's ability to use a stethoscope to recognize specific patterns and phenomena. Through advances in technology many of these abilities have been automated, however for some of these auscultation methods a stable automated procedure has yet to be found.
For diagnostic cardiac events one of the most interesting sounds is the second heart sound This sound comprises two components which are generally of interest: the aortic component and the pulmonary component. Detection and recognition of those components provides the possibility of measuring the systole and diastole duration for both the left- and right heart. These values are very important for many applications such as detection of pulmonary artery hypertension, dysfunction of heart valves, left and right ventricular dysfunction, etc.
As described hereinabove, the second heart sound and the components A2 and P2 thereof have significant clinical value. However, these components are very often masked by noises and other acoustic components of both the heart sounds and other parts of human body. As result, typically only specially trained and experienced clinicians can distinguish the A2 and P2 components. As a result, an automated computer-based procedure for A2 and P2 components would be desirable in clinical practice. One prior art reference, U.S. Pat. No. 6,368,283, reveals such a method. However, the proposed method is a non-automated human-assisted procedure which only works during periods of non-breathing.
Cardiac catheterisation and echocardiography, which have provided an accurate diagnosis of both right- and left heart abnormalities, have added a new dimension to usefulness of the phonocardiogram in assessing the presence and severity of cardiovascular abnormalities. Although cardiac catheterization generally provides the decisive evidence of the presence and severity of cardiac abnormalities, the external sound recordings correlate sufficiently well with the internal findings for them to serve, in many instances, as diagnostic tool per se. In this regard, phonocardiography often provides information complementary to that obtained by echocardiography. With this enhanced diagnostic accuracy, simpler and less painful external techniques can be used to determine when a patient needs more extensive cardiac treatment. Even in those cases where cardiac catheterisation is deemed necessary, the knowledge gained beforehand through phonocardiography and other non-invasive studies can lead to much more efficient and fruitful invasive study.